Small battery devices need magnetic switches that use power and take up space. These switches detect magnets and help devices run longer.
Engineers designing compact, battery-powered electronics often face a challenge with magnetic switches that consume too much power or require large magnets, limiting device size and battery life. Littelfuse’s omnipolar magnetic switches, the LF21173TMR and LF21177TMR, address this by combining TMR and CMOS technologies in a tiny LGA4 package.
The devices operate across a voltage range of 1.8 V to 5.5 V and support multiple magnetic thresholds, making them easier to integrate into space-limited designs. Compared with Hall-effect switches, these TMR-based switches offer higher sensitivity and lower power consumption, allowing engineers to create smaller devices with longer battery life.
TMR technology works differently from Hall-effect sensors. Instead of using Hall voltage, it measures resistance changes in magnetic tunnel junctions. This produces a stronger signal at lower currents, reducing power use while maintaining accuracy and thermal stability, which is useful for devices where energy efficiency matters.
The switches offer several advantages: low power consumption for extended battery life, high magnetic sensitivity that works with smaller magnets, a wide voltage range for flexible integration, fast response for precise real-time sensing, a compact LGA4 package that fits tight spaces, and omnipolar detection that senses both north and south poles, simplifying layout.
These devices are suited for a variety of applications. In healthcare, they can be used in glucose monitors and drug delivery pens. In building automation, they fit smart gas and water meters. Consumer electronics benefit from portable devices and robotic appliances, while industrial automation includes electronic locks and controls. They are also suitable for small vehicles and e-bikes in transportation.
“With the launch of the LF21173TMR and LF21177TMR switches, we’re bringing our customers a new level of precision and efficiency in magnetic sensing,” said Julius Venckus, Global Product Manager, Sensors at Littelfuse. “By integrating advanced TMR technology, this switch delivers ultra-low power consumption and high sensitivity—solving key challenges in compact, battery-powered designs. It’s a game-changer for engineers building smarter, more reliable devices in industrial, medical, and consumer applications.”
